USOO628745OB1 (12) United States Patent (10) Patent No.: US 6,287,450 B1 Hradil (45) Date of Patent: *Sep. 11, 2001

(54) APPARATUS AND METHOD FOR Primary Examiner Arun S. Phasge PURIFYING WATER WITH AN IMMERSED (74) Attorney, Agent, or Firm-Fuess & Davidenas GALVANIC CELL (57) ABSTRACT (76) Inventor: George Hradil, c/o Covofinish Company, 266 Davis Dr., Pascoag, RI A System and method Suitable for use in (US) 02859 Swimming pools, Spas, hot tubs, water Storage tanks, wells (*) Notice: Subject to any disclaimer, the term of this and water cooling towers employs a galvanic cell having a patent is extended or adjusted under 35 or or Zinc anode electrically connected to a U.S.C. 154(b) by 0 days. cathode made from a of Still higher electrochemical potential, normally a platinum group metal and preferably (21) Appl. No.: 09/237,553 palladium. A galvanic cell of Some tens of Square centime (22) Filed: Jan. 26, 1999 ters in size and Some hundreds of grams in weight liberates (51) Int. Cl." ...... CO2F 1/461 Sufficient Silver or copper ions So as to treat a multi-thousand (52) U.S. Cl...... 205/745; 204/242; 204/248 liter body of water, Such as a , for, typically (58) Field of Search ...... 205/745; 204/242, under normal contamination, Some months until the anode is 204/248 consumed. Copper and/or Silver ions liberated from the galvanic cell Suppress bacterial, fungal and/or growth, (56) References Cited thus, Significantly reducing the amount of , U.S. PATENT DOCUMENTS or other chemicals needed to maintain . The 4,416,854 11/1983 Nielsen ...... 205/745 invention operates on the current generated by the galvanic action between the dissimilar of the anode and FOREIGN PATENT DOCUMENTS cathode, and does not require external electrical power. 1440886 * 6/1976 (GB) ...... 205/745 * cited by examiner 11 Claims, 7 Drawing Sheets

U.S. Patent Sep. 11, 2001 Sheet 1 of 7 US 6,287,450 B1

FIGURE 1

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O O 5

O --- - rt -H-I-m---- O 2 4. 6 8 10 12 14 Hypochlorite Concentration (ppm) U.S. Patent Sep. 11, 2001 Sheet 2 of 7 US 6,287,450 B1

FIGURE 2

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O. 5 l

O1

O 50 1 OO 15 O 2OO 250 3OO Time (min) U.S. Patent Sep. 11, 2001 Sheet 3 of 7 US 6,287,450 B1

FIGURE3

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O .0 3

0.02

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O 100 200 3OO 400 500 600 Liquid Agitation (stirrer RPM) U.S. Patent Sep. 11, 2001 Sheet 4 of 7 US 6,287,450 B1

FIGURE 4

U.S. Patent Sep. 11, 2001 Sheet 5 of 7 US 6,287,450 B1

FIGURE 5A

16 Top View

13 CrOSS-Section A

FIGURE 5B U.S. Patent Sep. 11, 2001 Sheet 6 of 7 US 6,287,450 B1

FIGURE 6A

26 Top View 20

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CrOSS-Section B FIGURE 6B

US 6,287,450 B1 1 2 APPARATUS AND METHOD FOR pools, the cost of continued operation becomes prohibitive. PURIFYING WATER WITH AN IMMERSED Also, governmental restrictions apply and costs of installa GALVANIC CELL tion are high. Metallic ions are known to kill or control algae and REFERENCE TO RELATED PATENT . It is well established that Silver and copper ions are APPLICATIONS effective bactericides and algaecides. Treatment with Silver The present patent application is related to, and claims has been used by NASA to purify water on the Apollo space benefit of priority of, U.S. provisional patent application missions. The practice of using Silver and copper vessels to Serial No. 60/AAAAAA filed on Jan. 26, 1998 to the improve water quality dates back to ancient times. Ancient Selfsame inventor George Hradil of the present application. Phoenicians Stored wine in Silver urns to preserve it, pro Viding one the earliest recorded examples of use of this BACKGROUND OF THE INVENTION metal for that purpose. Zinc, aluminum, and gold ions are just a few additional metals that can be used similarly. 1. Field of the Invention Dahlegren, U.S. Pat. No. 4337136, (1982), purifies pool The present invention generally concerns water purifica 15 water by using a pair of Silver-copper alloy electrodes tion Systems. extending from a floating container. Electrical energy is The present invention particularly concerns the purifica provided by a battery, using a timer Switch that reverses the tion of water in Swimming pools, Spas, hot tubs, water current as required to reduce erosion of the electrodes. The Storage tanks, Wells and water cooling towers by use of operating life of Such a cell is limited by the requirement of galvanic cells in order to inhibit the growth of bacteria, batteries. and algae while Significantly reducing the amount of Sherman, in U.S. Pat. No. 5,085,753, describes a water chemicals (chlorine, bromine, hypochlorite, perSulfate, purifier with a buoyant housing for Supporting a purification oZone, etc.) necessary to maintain water quality. cell below the water's Surface and for Supporting a Solar cell 2. Description of the Previous Art array for providing power for the purification cell. The cell 2.1. Water Purification 25 operation includes electrolytic processes, electrocution and The paramount function of water treatment is to destroy oxidation to destroy bacteria and algae. harmful . This is usually accomplished by There are two types of undesirable elements in pool adding oxidizing agents Such as chlorine, iodine and . water: 1) impurities in Suspension, in the form of precipitates In Swimming pools and Spas, the treatment of water to or colloids, and 2) dissolved, extremely Small, electrically eliminate contamination ordinarily incorpo charged impurities in the ionic State. To eliminate these rates chemical treatment in combination with a mechanical impurities, flocculation processes-consisting of introduc filtering usually accomplished by drawing water from the ing a reactant into the water to create colloids with adsorp pool with a pump, forcing it through a filter and returning it tion properties-have been used. The colloids cause to the pool. Because the mere addition of a quantity of a 35 flocculation, which encloses the impurities in Suspension. chemical in liquid or Soluble form permits the circulation Large particles are formed and are separated from the water System to effectuate quick dispersal, Sanitization treatment is by filtering. To facilitate flocculation, the pH of the water has an easy task. Chlorine is typically used as a Sanitation agent. to be adjusted, in many cases, to below 7.4 or above 8.5. However, chlorine is malodorous, rather inefficient, 2.2. Water Purification With Metal Ions unhealthful, and not particularly economical. 40 Conventional purification devices use either (i) an excess At ordinary temperatures, chlorine is a gas, difficult to of anodic reaction products, (ii) a particular linear relation handle, and is not generally available. Accordingly, chlorine ship between purification cell current and treated water used in pools and ponds is combined with Some compound temperature, (iii) addition of Sodium perSulfate to water in that dissociates upon addition to pool water. Chlorine is which copper and Silver ions have been added from copper popularly introduced as a constituent of calcium 45 silver electrodes immersed in the water, or (iv) addition of hypochlorite, , chlorinated Salt in Sufficient quantities to make the water slightly con isocyanurates, or Some other acid, or as a Salt. If added as a ductive followed by circulating the slightly conductive water Salt, additional chemicals are required to avoid harmful through an electric field between a pair of electrode plates. accumulations of any other constituents of the Salt, resulting These conventional devices and methods have generally in the problematic requirement of maintaining a chemical 50 been uneconomical and inefficient, and have focused on balance. producing and regulating a DC current from an AC power The process of purification of pool water using electroly Source So as to maintain the Safety of Swimmers. The sis has already been developed, and is well known in the art. equipment is expensive, complicated and generally requires Shindell, in U.S. Pat. No. 4,328,084 (1982) describes a water Special installation and monitoring, thereby increasing purification System employing Salt in quantities Sufficient to 55 manufacturing, operating and liability insurance costs. make the water slightly conductive and circulating that Solar powered purification cells can overcome Some of water through the electric field between a pair of dissimilar these problems, However, other drawbackS Such as exces metal plates in order to dissociate Salt ions from the water. Sive gassing, corrosion, and accumulation of Scale and The dissociated ions of Salt and water are converted to deposits at the purification cell electrodes, result in reduced oxidizing agents capable of destroying organic matter, 60 efficiency, destruction of the cell and/or the necessity of which is converted to substances that can be removed by repetitively cleaning the electrodes. mechanical . The proceSS reportedly results in eco In U.S. Pat. 5,279,748, issued to Hackett, water is passed nomical and effective purification. However, a major prob through an “electrolytic filter consisting of packed granules lem arises when a purification cell is placed in the circulation of copper and Zinc, or "a copper-zinc filter media.” “AS piping. The pump must operate continuously to maintain an 65 water passes through the electrolytic granules, a chemical effective level of chlorine or oligodynamic ions. This is not reaction causes metal hydroxides to form in controlled a problem in large commercial pools, however, in residential amounts. These controlled releases of oxides are carried into US 6,287,450 B1 3 4 the filtered water where they kill bacteria and provide a unnecessary to recommend any health-based guidelines for hostile environment for algae and fungus growth.” The Silver, as it is not hazardous to human health. Silver ion amount of ionized metal entering the pool is controlled by generators are currently being used in intensive care and varying the flow rate of water entering the electrolytic filter heart transplant units of hospitals, and for poultry independent of the physical Straining filter. The electrolytic processing, engineering, brewing, cooling towers and Swim filter is impervious to the bacterial growth to which similar ming pools. filters (composed of other materials) can be Susceptible. According to the most recent research on the Swimming Hackett's device is claimed to eliminate the need for chlo pool industry, published in 1993 by the National Spa and C. Pool Institute, 6.6 million individuals in the United States U.S. Pat. No. 4,492,618 to Eder discloses a method in own pools, 3.4 million of which are in-ground and 3.2 which electrodes of a copper-Silver alloy are dissolved in the million are aboveground. NSPI estimates that approximately treated water via the application of a periodically reversed 160,000 in-ground pools are built annually in the United direct current. The electrically induced dissolution of the States, in addition to about 475,000 aboveground pools. electrodes liberates copper and Silver ions into the water. Silver-based mechanisms for keeping Swimming pools Sani Sodium persulfate is added to the water for the “oxidation of 15 tized are gaining widespread popularity among pool owners organic matter.” preoccupied with the mounting health hazards of chlorine. In U.S. Pat. No. 4,608,247 issued to Heinig, silver is Silver-copper ion Systems have Sanitized tens of thou deposited on a large Surface area Support and combined with Sands of Swimming pools worldwide for Several decades, carbon to produce a composition favorable to the dissolution inactivating including Bacillus typhosus, of silver ions in water. Legionella pneumophila and E. coli. Copper ions in the In U.S. Pat. No. 5,352,369, also issued to Heinig, a System have eliminated unwanted algae growth in pools, and method is described in which Silver deposited on a large have Supplemented Silver in controlling other , Surface area alumina matrix acts as a catalyst “in the Such as the polio . The technology works by producing presence of oxygen to form an active oxidizer in the water.” positively charged ions that attack and destroy the nega This active oxidizer is claimed to be effective in the con 25 tively charged cells of organisms like bacteria and algae. The tainment of bacterial and algal growth. positively charged ions also work by interfering with the LeMire, in U.S. Pat. No. 4,935,116, describes a device metabolism of organisms like bacteria and algae. consisting of concentric cylinders of dissimilar metals The purification method named the number one alterna (copper and Silver) that are electrically connected, with tive to chlorine, based on research conducted by Swimming provisions to pass water to be treated in the annulus of Said Pool and Spa Age magazine, is a Silver catalyst System that cylinders. The dissimilar metals form a voltaic cell whereby has the capacity to instantly destroy bacteria and . the metals are eroded to Supply copper and Silver ions to the The System deposits Silver microcrystals on the inside of a Water. flow-through cartridge, which feeds oxygen into the water 2.3. Silver Water Purification 35 flow. The oxidized silver destroys bacteria, viruses and Silver-based water purification systems offer the most organic matter. Tests performed by the U.S. Environmental reliable and cost-effective alternatives to chlorine, a chemi Protection Agency (EPA) at the University of Arizona, for cal that is increasingly coming under fire for the carcino example, found that the cartridge reduced the presence of E. genic byproducts it leaves in water. Because of increasing coli in water by 99.96 percent within five seconds. pollution, utilities are forced to put far more chlorine into the 40 The use of Silver in is growing Supply chain. Recently, chlorine has been shown to produce because of the many other advantages these Systems offer. by-products linked to cancer in laboratory animals, prompt Silver Systems are leSS expensive operationally than chlorine ing an immediate US government review. These same and other chemical Systems. Also, Silver does not evaporate byproducts have been generated by chlorination for a long from the water leaving the pool unprotected and does not time, but never in the quantities that are now being Seen. 45 Stain the Skin or clothing. In Britain, Silver ionization is being developed for main 2.4 Galvanic Cells Stream water Systems. Capitalizing on Silver's long-known It is known, by practitioners in the art, that each metal has biocidal properties and safety factors, the Institute of Water its own electrochemical potential. Additionally, it is known Ionization Technologies, UK, has developed Silver ion gen that when two dissimilar metals, each with different elec erators for municipal water Supplies. A recent project to 50 trochemical potentials are immersed in a conductive Solution Study the control of Legionnaires disease by using Silver and electrically connected together, a galvanic cell or battery ions was funded by the UK Department of the Environment. will be formed; Such that current will flow from the metal of The disease is named after Legionella pneurnophilia, an lower electrochemical (anode) potential to the metal of high that is widespread in Small quantities within chemical potential (cathode). Moreover, it is known that the natural water Sources. The bacteria is lethal at a water 55 metal of lower electrochemical potential will be dissolved temperature of 95 F., but can be killed at temperatures into the electrolyte at a rate proportional to the current between 135 and 140 F. Of the methods tested, silver/ flowing between the two electrodes. This process transpires copper ions in Soft water were found to be most effective. when a Strip of a metal Such as Silver is immersed in water The copper ion disrupted the enzyme structures of the cell, containing ionic Species. A Strip of another metal, Such as allowing the Silver ion to penetrate inside, where it rapidly 60 platinum, is immersed in the water and is electrically con inhibited the cell's life Support system. nected to the Silver Strip, commonly by wire via an ampere U.S. regulations allow a silver level of 100 ppb in meter. Current flows from the silver strip through the wire drinking water, but a silver level of only 20 ppb kills and ampere meter to the platinum Strip due to the potential Legionella. A proposed European Union Drinking Water difference between the two metals. At the Surface of the Standard has removed any upper limit for Silver in drinking 65 Silver Strip metallic Silver atoms lose electrons to form Silver water, following the World Health Organization's Guide ions. The electrons liberated by the oxidation of metallic lines for Drinking Wafer Quality, which determined that it is silver flow through the electrical connection between the US 6,287,450 B1 S 6 two metals, comprising a current which can be detected by chemistry handbook. However, if the anode metal is to be the ampere meter. At the Surface of the platinum, electrons Silver which has a very high electrochemical potential, then typically react with oxidizing Species, Such as hypochlorite this is a demanding requirement. Of common elements, only ions. gold, palladium and platinum have a higher electrochemical A galvanic cell is a simple and effective means of intro potential than does Silver. ducing Small quantities of beneficial metal ions into water. The precise mechanism of the biocide effect is not known What has been misunderstood by previous investigators with respect to this invention. Experiments have shown that (LeMire and Hackett) is that the metal of higher electro the amount of Silver liberated to the Solution is minuscule, chemical potential is cathodically protected by the flow of and yet, pool trials have found a significant beneficial effect. current in the galvanic cell and is therefore inhibited from It is believed that the effect is due to Surface-adsorbed silver dissolving. In fact, this effect is exploited in galvanized Steel complexes, rather than dissolved Silver in the pool water. and in other applications Such as the use of a Sacrificial Zinc Calculations have indicated that only 0.1 to 0.05 grams of electrode for underground tank and marine applications. Silver are required to form an adsorbed monolayer in a Therefore, the devices described by LeMire and Hackett will typical pool. The occurrence of temporary photoSensitive only be effective in dissolving the metal of lower chemical 15 discoloration of the pool or Spa Surface further evidences the potential. Silver, which has a relatively high electrochemical likelihood of Surface adsorption of silver. potential, will not be appreciably dissolved. Accordingly, in accordance with the present invention a water purification device is realized as a galvanic cell SUMMARY OF THE INVENTION consisting of two metals: 1) a first metal drawn from the The present invention contemplates immersing and oper group consisting essentially of Silver, copper and Zinc, in ating a two-metal twoelectrode galvanic cell in water ren electrical contact with 2) a Second metal having a higher dered electrically conductive by the presence of ions of, for electrochemical potential than does the first metal. The example, chlorine where the anode of the galvanic cell (i) is Second metal is most commonly a member of the platinum the metal with the higher electrochemical potential, and group, or gold. The device is immersed in the electrically work function, and (ii) is sacrificial, liberating metal ions of 25 conductive water. An effective amount of the first metal is a type Suitable for water purification. The anode metal is liberated into the water by galvanic action So as to Serve to typically silver, copper or Zinc, and the cathode metal a inhibit the growth of bacteria, fuingi and algae. platinum group metal, preferably palladium. The metal ions In its preferred embodiment, the water purification device liberated from the galvanic cell serve to inhibit the growth is compactly packaged as, preferably, two metal mesh grids, of bacteria, fungi and algae. Screens, Strips or shot, or any combination thereof, that are Accordingly, one object of the present invention is an overlaid permanently one upon the other, or otherwise improved water purification System that is capable of remov positioned in physical and electrical contact. The two mesh ing water-borne micro-organisms from pools, spas, hot tubs, grids-one of which is made of one metal as the anode and lakes, ponds, and marshes without the need to add additional the other of which is made of another metal as the cathode chemical to chemically balance the water. 35 of a galvanic cell-are thus in physical and electrical contact Another object of the present invention is a water puri with each other over a Substantial area. Nonetheless to this fication device that Substantially eliminates complicated Substantial area of contact, Voids in the mesh grids permit circuits, hardware, and other unnecessary equipment. the ready circulation of water and of the ions contained Still another object is to provide considerable energy within the water. The device is generally used in water Savings over in-line chlorinators, particularly during times 40 rendered electrically conductive by the presence of chlorine of low or no water contamination. ions, particularly in mass bathing basins including Swim Yet another object of the invention is scalability in water ming pools, Spas, and hot tubs. purification, permitting usage of fewer purification cells in The water purification device of the present invention is Small reservoirs and more purification cells in larger reser 45 preferably used in a mass bathing basin that has a recircu voirs. lation system, and is located in line with the flow of the In order to accomplish the aforementioned and other recirculation system. The flow makes that the electrodes of objects, the Self-contained, inexpensive water purification the device are continually exposed to new conductive ions in device of the present invention is generally Suitable for use the water, and that the Zinc, copper or Silver ions liberated in all reservoirs of water that have been rendered electrically 50 from the anode are promptly transmitted away and dispersed conductive by the presence of ions. The galvanic action into the body of water. between dissimilar metals (typically silver, copper or Zinc In the case of a mass bathing basin having a chlorination and a platinum group metal, Such as palladium) immersed in point within the recirculation System, the device is prefer the electrically conducting Solution is used, as in the prior ably located directly downstream from the chlorination point art, to liberate metal ions. The metal ions may even be, and 55 within the recirculation System. This location makes that the most commonly are, the Selfsame Silver, copper or Zinc ions electrodes of the device are not only continually exposed to long recognized to be Safe and effective for purifying water. conductive chlorine ions in the water, but are exposed to However, unlike the prior art, the liberated metal comes these ions at the location of their highest density. from the anode, and not the cathode, of the galvanic cell. If In a most preferred embodiment, a water purification the galvanic cell is to function as Such, and without any 60 device for use in a Swimming pool having a chlorination external Source of electrical potential, this means that the point within a recirculation System is contemplated. The metal or other material of the cathode must have a greater device employs a first grid made of a first metal from the electrochemical potential, or work function, than does the group consisting of Zinc, Silver and copper in electrical anode metal. If the anode metal is Zinc, which has a contact with a Second grid made of a Second metal having a relatively low electrochemical potential, or copper, which 65 higher electrochemical potential than does the first metal. A has a higher electrochemical potential, then this requirement mechanism for retaining both grids together as a galvanic may be met by Several metals that may be located in any cell is also contemplated. The galvanic cell device is US 6,287,450 B1 7 8 immersed in flowing water in a position directly downstream via an ampere meter (5) and associated wire (4). Current from the chlorination point within the Swimming pool's flows from the silver strip (6) through the ampere meter (5) recirculation System. Therein, by galvanic action, a Sufficient to the platinum Strip due to the potential difference between amount of the first metal is liberated into water of the the two metals. At the surface of the silver strip (6) metallic Swimming pool So as to Serve as inhibitor of the growth of Silver atoms lose electrons to form Silver ions. The electrons bacteria, fungi and algae. liberated by the oxidation of metallic silver flow through the The present invention is also embodied in a method of electrical connection between the two metals, comprising a generating aqueous metal ions, by action of which ions current which can be detected by the ampere meter (5). At water is purified. The method includes immersing, within the Surface of the platinum, electrons typically react with water rendered electrically conductive by the presence of oxidizing Species, Such as hypochlorite ions. ions, a galvanic cell consisting essentially of a first metal, In a preferred embodiment of the present invention, drawn from the group of Zinc, Silver and copper, that is in dissimilar metals (typically Zinc, copper or Sliver in combi electrical contact with a Second metal having a higher nation with a platinum group metal or gold) are maintained electrochemical potential than does the first metal. An effec in electrical contact with each other and retained in a tive amount of the first metal is liberated into the water by 15 container. The container is immersed within a reservoir of galvanic action as first metal ions So as to Serve as inhibitor water—which water has already been rendered electrically of the growth of bacteria, fungi and algae. conductive by the presence of ions-that is to be treated. The These and other aspects and attributes of the present metals may consist of metal foil, expanded mesh, shot, wire, invention will become increasingly clear upon reference to metal wool, or any other form of metal presenting a large the following drawings and accompanying Specification. Surface area. The dissimilar metals are in electrical contact, thereby, forming a galvanic cell which dissolves over time BRIEF DESCRIPTION OF THE DRAWINGS the metal of lower electrochemical potential (typically Zinc, copper or silver), consuming over time the anode of the Referring particularly to the drawings for the purpose of galvanic cell, which is Sacrificed. The cathode metal illustration only and not to limit the Scope of the invention 25 (typically relatively inert gold or a platinum group metal, in any way, these illustrations follow: Such as palladium) neither dissolves nor dissipates. FIG. 1 is a plot of the current between silver and platinum The container may simply be placed below the skimmer as a function of hypochlorite concentration. basket of the Swimming pool or Spa, or may be placed FIG. 2 is a plot of the silver concentration as a function anywhere in the body of water to be treated. Alternately, the of time during the galvanic cell reaction between platinum dissimilar metals in electrical contact with one another may and Silver. be placed in a chamber through which the water to be treated FIG. 3 is a plot of the current between silver and platinum is circulated by means of a pump. Typically, the device will as a function of liquid agitation. be a mixed packing of silver metal and a platinum group FIG. 4 is a Schematic diagram of a common galvanic cell metal (e.g., palladium). An additional mixed packing of having Silver and platinum electrodes. 35 copper and a platinum group metal may be employed to FIG. 5A is a top view of an embodiment of the current provide copper ions to the water. Furthermore, a mixed invention. packing of copper, Silver and a platinum group metal may also be used. FIG. 5B is a cross-sectional view of FIG. 5A taken at It has also been found that the rate of metal dissolution is aspect line A-A. 40 greater as the concentration of hypochlorite ions or other FIG. 6A is a top view of another embodiment of the oxidizers in the water is increased. It is therefore desirable invention incorporating a chlorine dispenser. to situate the packing of dissimilar metals at the point of FIG. 6B is a cross-sectional view of FIG. 6A taken at chlorination or where other oxidizing agents are added to the Aspect line B-B. pool. This may be accomplished by incorporating the dis FIG. 7A is a top view of another preferred embodiment of 45 Similar metals into a chlorine dispenser, thereby exposing the invention. the mixed metal packing to the water at point of its highest FIG. 7B is a cross-sectional view of FIG. 7A taken at ionic strength. This device would then provide both chlorine aspect line C-C. and metal ions to the water to be treated. Alternatively, this can be accomplished by locating the metallic packing in a DESCRIPTION OF THE PREFERRED 50 chamber in-line with the pool or Spa recirculation System EMBODIMENT directly downstream of the chlorination point. Although specific embodiments of the invention will now In any case, the metal dissolution rate is increased if the be described with reference to the drawings, it should be metal packing is exposed to water having higher concentra understood that Such embodiments are by way of example 55 tions of oxidizing ions. It has also been demonstrated that only and are merely illustrative of but a small number of the the dissolution rate is dependent on the Velocity of the many possible Specific embodiments to which the principles treated water with respect to the metal Surface; therefore, it of the invention may be applied. Various changes and is desirable to enhance the liquid contacting of the device to modifications obvious to one skilled in the art to which the the water to be treated. It is possible to enhance both the invention pertains are deemed to be within the Spirit, Scope 60 liquid contacting and the concentration of oxidizing ions by and contemplation of the invention as further defined in the combining the galvanic cell with a chlorine dispenser which appended claims. is recirculating a stream of the water to be treated. The process of monitoring galvanic action is illustrated in One possible implementation of the invention is a perfo FIG. 4 where a strip of, by way of example, silver metal (6) rated container which incorporates a chamber where a mixed is immersed in water containing ionic species (3). A Strip of, 65 packing of Silver and platinum are retained and which by way of example, platinum metal is immersed in Said further features a chamber where calcium hypochlorite water (3) and is electrically connected to the silver strip (6) powder or tablets could be held. This container could be US 6,287,450 B1 9 10 placed in or below the skimmer basket or in the inlet Strainer and the divider have slots (26) which allow the water to of the filtration pump. In this way, both high oxidizer circulate through the enclosure. The top Section of the device concentration as well as excellent liquid contacting can be (20) is removable to allow the user to replenish the maintained. hypochlorite tablets (30). The device may be placed in the skimmer basket of the pool or in the inlet strainer of the filter EXAMPLE ONE pump, or alternatively may simply be placed anywhere below the water Surface. A strip of 2.5 cm by 5.0 cm silver metal foil and a 2.5 cm by 5.0 cm strip of platinized niobium expanded mesh were FIG. 7a depicts a top view of a most preferred embodi immersed in 200 mls of DI water. The silver and platinum ment of a package of the galvanic cell in accordance with the Strips were Separated by 0.5 mm thick polypropylene mesh present invention. FIG.7b is a cross-sectional view of FIG. and are electrically connected via a Volt/ampere meter. The 7a, taken at aspect line C-C, depicting the layers of an Solution was agitated with a magnetic Stirrer while a dilute anodic metal (14) juxtapositioned to a cathodic metal (14a) solution of sodium hypochlorite was titrated into the DI Sandwiched between two polyethylene or nylon layerS form water. The potential (voltage) and the current between the ing a pouch. The package may be either Square or circular in metals was recorded as a function of Sodium hypochlorite 15 shape. concentration. The results for pH 7.0, 7.5, and 8.0 are shown Basic Start-up instructions for the use of the galvanic in FIG. 1. Sanitizer that is the present invention are as follows: Clean the debris and algae from the pool and equipment, EXAMPLE TWO Balance the pool water as normal, A strip of 2.5 cm by 5.0 cm silver metal and a 2.5 cm by Add one unit (packet) of this invention to the skimmer for 5.0 cm Strip of platinized niobium expanded mesh was every 25,000 gallons of pool water, immersed in 200 mls of DI water containing 5.25 ppm of Start with new packets only once at the beginning of each Sodium hypochlorite. The solution pH is 7.5. The silver and SeaSOn, platinum Strips were separated by 0.5 mm thick polypropy After approximately 14 days, begin to cut back on chlo lene mesh and were electrically connected via a Volt/ampere 25 rine usage. meter. The Solution was agitated with a magnetic Stirrer. The In accordance with the preceding explanation, variations potential was 0.47 V and the current was 0.066 mA. The and adaptations of the water purification device in accor Solution was analyzed for Silver every 30 minutes using an dance with the present invention will Suggest themselves to Atomic Absorption Spectrometer. The results are shown in a practitioner of the water Sanitization arts. FIG. 2. The measured silver dissolution rate is 5% to 15% In accordance with these and other possible variations and of the theoretical amount calculated from the measured adaptations of the present invention, the Scope of the inven Current. tion should be determined in accordance with the following claims, only, and not Solely in accordance with that embodi EXAMPLE THREE 35 ment within which the invention has been taught. A strip of 2.5 cm by 5.0 cm silver metal and a 2.5 cm by What is claimed is: 5.0 cm Strip of platinized niobium expanded mesh were 1. A water purification device for use in water rendered immersed in 200 mls of DI water containing 5.25 ppm of electrically conductive by the presence of ions but with So Sodium hypochlorite. The solution pH was 7.5. The silver few ions as to permit acidity to remain within a range Suitable for a Swimming pool, the device comprising: and platinum Strips were Separated by 0.5 mm thick polypro 40 pylene mesh and were electrically connected via a Volt/ a galvanic cell consisting essentially of ampere meter. The Solution was agitated with a magnetic a first metal drawn from the group of Silver and copper stirrer. The stir bar rotation rate was varied and the corre and Zinc, in physical and electrical contact with sponding current was recorded to determine the dependence a Second metal having a higher electrochemical potential of Silver dissolution on the liquid shear rate. The results are 45 than does the first metal, shown in FIG. 3. where at least one of the first metal and the Second metal Now, turning in greater detail to the two embodiments of is in the form of a planar mesh while the other metal is the invention depicted in the appended drawings, FIGS. 5a also in a planar form laid flat against the mesh, and 5b show one possible implementation of the current immersed in the water rendered electrically conductive invention. A mixed packing of Strips of platinized foil and 50 by the presence of ions, silver foil (14) is retained in a polyethylene or nylon mesh wherein openings within the at least one mesh permit pouch (15). The plastic pouch is contained in a hard case circulation of the water so that the ions within the water with top and bottom sections (11) and (13) respectively. may readily come into contact with both the first and Both the top (11) and bottom (13) sections have slots (16) to the second metals where there is little distance between allow liquid flow through the case (FIG. 5a). The device 55 them; may be placed below the skimmer basket of the pool or in wherein by galvanic action an effective amount of the first the inlet strainer of the filter pump. metal is liberated into the water So as to Serve as to FIGS. 6a and 6b illustrate an embodiment of the current inhibit the growth of bacteria, fungi and algae. invention in which the galvanic cell is incorporated into a 2. The water purification device according to claim 1 chlorine dispenser. The outer casing consists of two Sections 60 wherein the galvanic cell's Second metal consists essentially (20) and (24). A mixture of platinized (a coating 10-100 of a metal of the platinum group. millionths of an inch thick plated, clad or electroplated on 3. The water purification device according to claim 2 niobium or stainless steel) and silver foil strips (14) is wherein the galvanic cell's Second metal of the platinum encapsulated by a polyethylene or nylon mesh pouch (15). group consists essentially of palladium. The most preferred metal for the platinized coating is 65 4. The water purification device according to claim 1 in palladium. The mesh pouch (15) is separated from the use in chlorinated water rendered electrically conductive by hypochlorite tablets (30) by a divider (22). The outer casing the presence of chlorine ions. US 6,287,450 B1 11 12 5. The water purification device according to claim 4 in contact, permitting galvanic action to transpire none use in a mass bathing basin including Swimming pools, Spas, theless that concentration of chlorine should be low. and hot tubs. 10. (Amended) A method of generating aqueous metal 6. The water purification device according to claim 5 in ions by action of which water is purified, the method use in a mass bathing basin having a recirculation System, 5 comprising: the device being located in line with a flow of water immersing a galvanic cell consisting essentially of containing ions through the recirculation System; a first metal drawn from the group of Silver and copper and Zinc, in electrical and physical contact with wherein flow of the water containing ions through the at a Second metal having a higher electrochemical poten least one mesh, and into regions between the first and tial than does the first metal, the Second metals, is promoted by flow in the recircu where at least one of the first metal and the Second lation System. metal is in the form of a planar mesh while the other 7. The water purification device according to claim 5 in metal is also in a planar form laid flat against the use in a mass bathing basin having a chlorination point mesh, within flowing water rendered electrically within the recirculation System, the device being located conductive by the presence of a low concentration of directly downstream from the chlorination point within the 15 ions, recirculation Systems; wherein by galvanic action transpiring where the first wherein concentration of ions in the water is relatively metal contacts the Second metal in presence of occa high at locations of the first metal and the Second metal, Sional ions as do come into contact from the water promoting galvanic action between the first metal and flowing through the at least one mesh, an effective the Second metal. amount of the first metal is liberated into the water as 8. The water purification device according to claim 1 first metal ions So as to Serve as to inhibit the growth of where the both the first metal and the second metal are in the bacteria, fungi and algae nonetheless that the concen form of a planar mesh. tration of ions is low. 9. A water purification device for use in a Swimming pool 11. A water purification device for use in water rendered having a chlorination point within a recirculation System, the 25 electrically conductive by the presence of a low concentra device comprising: tion of ions, the device comprising: a first grid made of a first metal from the group consisting a galvanic cell consisting essentially of of Silver and copper and Zinc, in electrical contact with a first mesh of a first metal drawn from the group of Silver and copper and Zinc, in physical and electrical a Second grid made of a Second metal having a higher contact with electrochemical potential than does the first metal; and a Second mesh of a Second metal drawn from the means for retaining both grids closely physically proxi platinum group, and thus having a higher electro mate and electrically connecting as a galvanic cell chemical potential than the first metal, immersed in immersed in flowing water in a position directly down the water rendered electrically conductive by the stream from the chlorination point within the Swim 35 presence of the low concentration of ions, ming pool's recirculation System; wherein by galvanic action transpiring where the first wherein by galvanic action a Sufficient amount of the first metal contacts the Second metal in presence of occa metal is liberated into water of the Swimming pool So Sional ions as do come into contact from the water as to Serve as to inhibit the growth of bacteria, fungi and flowing through both the first and the Second meshes, algae So that use of chlorine in the Swimming pool is 40 an effective amount of the first metal is liberated into reduced; the water so as to serve as to inhibit the growth of meanwhile that, because of both (i) location and (ii) bacteria, fungi and algae nonetheless that the concen geometry of the grids, (a) chlorine ions as are within the tration of ions is low. Swimming pool water may freely contact both (b) the first metal and the Second metal which are in electrical